Electron
An electron is a fundamental subatomic particle with a negative electric charge, found in atoms and responsible for electricity and chemical bonding.
How big is it?
9.109 × 10⁻³¹ kg in mass
Mass · measured constant
A little perspective
Proton is about 1,840 times larger on this measurement.
Proton: A proton is a positively charged particle found in the nucleus of atoms, made up of quarks.
Measurements, assumptions & sources +
Electron
The length shown is the electron Compton wavelength, not its diameter. In the Standard Model the electron is treated as pointlike; the cloud is a schematic.
NIST — 2022 CODATA fundamental constants
The marked mass is calibrated. Unmeasured illustration details are representative.
Proton
Twice the approximately 0.8409 fm charge radius. The charge distribution has no hard boundary; the illustration is schematic.
NIST — 2022 CODATA fundamental constants
The marked mass is calibrated. Unmeasured illustration details are representative.
Change your perspective
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Choose a suggestion to redraw the comparison, or open its page to learn what it is.
Why this measurement?
Why we use 9.109 × 10⁻³¹ kg
For comparison, this page uses mass. This is labelled measured constant; the central value is useful for comparison, while real values or measurement solutions can vary.
The length shown is the electron Compton wavelength, not its diameter. In the Standard Model the electron is treated as pointlike; the cloud is a schematic.
The identifying illustration and the numerical comparison remain separate. How calibrated comparisons work →
Recorded properties
Electron dimensions and measurements
| Property | Selected value | Recorded range | Basis |
|---|---|---|---|
| 9.109 × 10⁻³¹ kg | Not recorded | measured constant | |
| 2.426 pm | Not recorded | measured constant |
Around this scale
Go smaller. Go bigger.
These links use compatible mass records, ordered around the selected value.
Sources and method
Want to check the number?
The source records and measurement method remain available for inspection.
- NIST — 2022 CODATA fundamental constantsRecommended constants with uncertainties; exact SI definitions are distinguished from measured constants.
More ways to see it
Curated comparisons
There’s always another scale
Follow your curiosity.
Fundamental physicsPlanck length1.616 × 10⁻³⁵ mThe Planck length is a scale formed from fundamental physical constants.
MicroscopicHydrogen atom105.8 pmA hydrogen atom is the simplest neutral atom, with one proton in its nucleus and one electron around it.
MicroscopicDNA double helix2 nmDNA is the molecule that stores hereditary information in living organisms.
Fundamental physicsProton1.682 fmA proton is a positively charged particle found in the nucleus of atoms, made up of quarks.
Fundamental physicsNeutron1.675 × 10⁻²⁷ kgA neutron is a type of subatomic particle found in atomic nuclei, carrying no electric charge and playing a key role in holding nuclei together.
MicroscopicWater molecule280 pmA water molecule is a group of two hydrogen atoms bonded to one oxygen atom.
MicroscopicGlucose molecule1 nmA glucose molecule is a simple sugar used by living cells as a source of chemical energy.
MicroscopicVirus100 nmA virus is an infectious particle containing genetic material inside a protein coat, sometimes with an outer envelope.